Reminds me of Single-Side Band HF radio carrier that I used to hear when tuning across the short wave frequencies looking for radio amateur ("HAM") operators, international aircraft traffic, the BBC, VoA, Radio Moscow, whatever, in my pre-Internet youth of the 1960s.

So who you gonna call .... ?

Aubrey

The illiterate of the 21st century will not be those who cannot read and write, but those who cannot learn, unlearn, and relearn. Alvin Toffler, "Future Shock" 1970